Question

38 ml of a mixture of CO and H2 was exploded with 31 ml of O2. The volume after explosion was 29 ml which reduced to 12 ml when shaken with KOH. Find percentage of CO and H2 in the mixture

Answer 1

The gaseous mixture contains (10ml of CO+ 4 ml of CH4 + 6 ml of N2) = 20 ml


The solution is as follows:


Let x ml of CO, y ml of CH4 and Z ml of N2 be present in the mixture.


Then x + y+ z = 20 ml ----(1)


x ml of CO needs (x/2) ml of O2 ; y ml of CH4needs 2y ml of O2


Total O2 used up during combustion is (x/2)+2y


It is to be noted that, 1 mole of CO gives 1 mole of CO2 and 1 mole of CH4 gives 1 mole of CO2. So, the overall reduction in volume of 13 ml is due to consumption of O2.


So, (x/2)+2y = 13 ml ----(2)


Solve for x and y using equations (1) and (2) . We get x = 10 ml and y= 4 ml.


So, volume of N2 = z= 6 ml.